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FKIE_CVE-2026-31498

Vulnerability from fkie_nvd - Published: 2026-04-22 14:16 - Updated: 2026-06-17 10:33
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix ERTM re-init and zero pdu_len infinite loop l2cap_config_req() processes CONFIG_REQ for channels in BT_CONNECTED state to support L2CAP reconfiguration (e.g. MTU changes). However, since both CONF_INPUT_DONE and CONF_OUTPUT_DONE are already set from the initial configuration, the reconfiguration path falls through to l2cap_ertm_init(), which re-initializes tx_q, srej_q, srej_list, and retrans_list without freeing the previous allocations and sets chan->sdu to NULL without freeing the existing skb. This leaks all previously allocated ERTM resources. Additionally, l2cap_parse_conf_req() does not validate the minimum value of remote_mps derived from the RFC max_pdu_size option. A zero value propagates to l2cap_segment_sdu() where pdu_len becomes zero, causing the while loop to never terminate since len is never decremented, exhausting all available memory. Fix the double-init by skipping l2cap_ertm_init() and l2cap_chan_ready() when the channel is already in BT_CONNECTED state, while still allowing the reconfiguration parameters to be updated through l2cap_parse_conf_req(). Also add a pdu_len zero check in l2cap_segment_sdu() as a safeguard.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/042e2cd4bb11e5313b19b87593616524949e4c52Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/25f420a0d4cfd61d3d23ec4b9c56d9f443d91377Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/52667c859fe33f70c2e711cb81bbd505d5eb8e75Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/900e4db5385ec2cacd372345a80ab9c8e105b3a3Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9760b83cfd24b38caee663f429011a0dd6064fa9Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9a21a631ee034b1573dce14b572a24943dbfd7aePatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/de37e2655b7abc3f59254c6b72256840f39fc6d5Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e7aab23b7df89a3d754a5f0a7d2237548b328bd0Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 5.7
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
To clipboard 

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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix ERTM re-init and zero pdu_len infinite loop\n\nl2cap_config_req() processes CONFIG_REQ for channels in BT_CONNECTED\nstate to support L2CAP reconfiguration (e.g. MTU changes). However,\nsince both CONF_INPUT_DONE and CONF_OUTPUT_DONE are already set from\nthe initial configuration, the reconfiguration path falls through to\nl2cap_ertm_init(), which re-initializes tx_q, srej_q, srej_list, and\nretrans_list without freeing the previous allocations and sets\nchan-\u003esdu to NULL without freeing the existing skb. This leaks all\npreviously allocated ERTM resources.\n\nAdditionally, l2cap_parse_conf_req() does not validate the minimum\nvalue of remote_mps derived from the RFC max_pdu_size option. A zero\nvalue propagates to l2cap_segment_sdu() where pdu_len becomes zero,\ncausing the while loop to never terminate since len is never\ndecremented, exhausting all available memory.\n\nFix the double-init by skipping l2cap_ertm_init() and\nl2cap_chan_ready() when the channel is already in BT_CONNECTED state,\nwhile still allowing the reconfiguration parameters to be updated\nthrough l2cap_parse_conf_req(). Also add a pdu_len zero check in\nl2cap_segment_sdu() as a safeguard."
    }
  ],
  "id": "CVE-2026-31498",
  "lastModified": "2026-06-17T10:33:51.470",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-04-22T14:16:48.067",
  "references": [
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    },
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      "url": "https://git.kernel.org/stable/c/e7aab23b7df89a3d754a5f0a7d2237548b328bd0"
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-835"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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